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Subject[PATCH 4.16 103/110] x86/bugs: Unify x86_spec_ctrl_{set_guest,restore_host}
Date
4.16-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Borislav Petkov <bp@suse.de>

commit cc69b34989210f067b2c51d5539b5f96ebcc3a01 upstream

Function bodies are very similar and are going to grow more almost
identical code. Add a bool arg to determine whether SPEC_CTRL is being set
for the guest or restored to the host.

No functional changes.

Signed-off-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
arch/x86/include/asm/spec-ctrl.h | 33 ++++++++++++++++++---
arch/x86/kernel/cpu/bugs.c | 60 +++++++++------------------------------
2 files changed, 44 insertions(+), 49 deletions(-)

--- a/arch/x86/include/asm/spec-ctrl.h
+++ b/arch/x86/include/asm/spec-ctrl.h
@@ -13,10 +13,35 @@
* Takes the guest view of SPEC_CTRL MSR as a parameter and also
* the guest's version of VIRT_SPEC_CTRL, if emulated.
*/
-extern void x86_spec_ctrl_set_guest(u64 guest_spec_ctrl,
- u64 guest_virt_spec_ctrl);
-extern void x86_spec_ctrl_restore_host(u64 guest_spec_ctrl,
- u64 guest_virt_spec_ctrl);
+extern void x86_virt_spec_ctrl(u64 guest_spec_ctrl, u64 guest_virt_spec_ctrl, bool guest);
+
+/**
+ * x86_spec_ctrl_set_guest - Set speculation control registers for the guest
+ * @guest_spec_ctrl: The guest content of MSR_SPEC_CTRL
+ * @guest_virt_spec_ctrl: The guest controlled bits of MSR_VIRT_SPEC_CTRL
+ * (may get translated to MSR_AMD64_LS_CFG bits)
+ *
+ * Avoids writing to the MSR if the content/bits are the same
+ */
+static inline
+void x86_spec_ctrl_set_guest(u64 guest_spec_ctrl, u64 guest_virt_spec_ctrl)
+{
+ x86_virt_spec_ctrl(guest_spec_ctrl, guest_virt_spec_ctrl, true);
+}
+
+/**
+ * x86_spec_ctrl_restore_host - Restore host speculation control registers
+ * @guest_spec_ctrl: The guest content of MSR_SPEC_CTRL
+ * @guest_virt_spec_ctrl: The guest controlled bits of MSR_VIRT_SPEC_CTRL
+ * (may get translated to MSR_AMD64_LS_CFG bits)
+ *
+ * Avoids writing to the MSR if the content/bits are the same
+ */
+static inline
+void x86_spec_ctrl_restore_host(u64 guest_spec_ctrl, u64 guest_virt_spec_ctrl)
+{
+ x86_virt_spec_ctrl(guest_spec_ctrl, guest_virt_spec_ctrl, false);
+}

/* AMD specific Speculative Store Bypass MSR data */
extern u64 x86_amd_ls_cfg_base;
--- a/arch/x86/kernel/cpu/bugs.c
+++ b/arch/x86/kernel/cpu/bugs.c
@@ -151,55 +151,25 @@ u64 x86_spec_ctrl_get_default(void)
}
EXPORT_SYMBOL_GPL(x86_spec_ctrl_get_default);

-/**
- * x86_spec_ctrl_set_guest - Set speculation control registers for the guest
- * @guest_spec_ctrl: The guest content of MSR_SPEC_CTRL
- * @guest_virt_spec_ctrl: The guest controlled bits of MSR_VIRT_SPEC_CTRL
- * (may get translated to MSR_AMD64_LS_CFG bits)
- *
- * Avoids writing to the MSR if the content/bits are the same
- */
-void x86_spec_ctrl_set_guest(u64 guest_spec_ctrl, u64 guest_virt_spec_ctrl)
+void
+x86_virt_spec_ctrl(u64 guest_spec_ctrl, u64 guest_virt_spec_ctrl, bool setguest)
{
- u64 host = x86_spec_ctrl_base;
+ struct thread_info *ti = current_thread_info();
+ u64 msr, host = x86_spec_ctrl_base;

/* Is MSR_SPEC_CTRL implemented ? */
- if (!static_cpu_has(X86_FEATURE_MSR_SPEC_CTRL))
- return;
-
- /* SSBD controlled in MSR_SPEC_CTRL */
- if (static_cpu_has(X86_FEATURE_SPEC_CTRL_SSBD))
- host |= ssbd_tif_to_spec_ctrl(current_thread_info()->flags);
-
- if (host != guest_spec_ctrl)
- wrmsrl(MSR_IA32_SPEC_CTRL, guest_spec_ctrl);
-}
-EXPORT_SYMBOL_GPL(x86_spec_ctrl_set_guest);
-
-/**
- * x86_spec_ctrl_restore_host - Restore host speculation control registers
- * @guest_spec_ctrl: The guest content of MSR_SPEC_CTRL
- * @guest_virt_spec_ctrl: The guest controlled bits of MSR_VIRT_SPEC_CTRL
- * (may get translated to MSR_AMD64_LS_CFG bits)
- *
- * Avoids writing to the MSR if the content/bits are the same
- */
-void x86_spec_ctrl_restore_host(u64 guest_spec_ctrl, u64 guest_virt_spec_ctrl)
-{
- u64 host = x86_spec_ctrl_base;
-
- /* Is MSR_SPEC_CTRL implemented ? */
- if (!static_cpu_has(X86_FEATURE_MSR_SPEC_CTRL))
- return;
-
- /* SSBD controlled in MSR_SPEC_CTRL */
- if (static_cpu_has(X86_FEATURE_SPEC_CTRL_SSBD))
- host |= ssbd_tif_to_spec_ctrl(current_thread_info()->flags);
-
- if (host != guest_spec_ctrl)
- wrmsrl(MSR_IA32_SPEC_CTRL, host);
+ if (static_cpu_has(X86_FEATURE_MSR_SPEC_CTRL)) {
+ /* SSBD controlled in MSR_SPEC_CTRL */
+ if (static_cpu_has(X86_FEATURE_SPEC_CTRL_SSBD))
+ host |= ssbd_tif_to_spec_ctrl(ti->flags);
+
+ if (host != guest_spec_ctrl) {
+ msr = setguest ? guest_spec_ctrl : host;
+ wrmsrl(MSR_IA32_SPEC_CTRL, msr);
+ }
+ }
}
-EXPORT_SYMBOL_GPL(x86_spec_ctrl_restore_host);
+EXPORT_SYMBOL_GPL(x86_virt_spec_ctrl);

static void x86_amd_ssb_disable(void)
{

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